Have these defined in the JSON files themselves, instead of trying
to add them from JS while minding the differences in number of levels
and rows.
This means more redundant data in the JSON files, but simplifies
OSK layout creation significantly, and allows finer control over the
appearance without quirks.
As a result, importing data from CLDR is no longer as straightforward
as running an script. After initial import, manual editions will be
required to add missing keys, assign key widths, and so on.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2278>
